JP2004047540A - Heat treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat treatment apparatus which includes a heat insulator to reduce amount of heat to be transferred in view of expanding a soaking region and increasing the number of processing objects to be processed. <P>SOLUTION: The heat treatment apparatus comprises a furnace body 11, having a furnace port 12 at the one end side thereof, a boat 30 arranged in the other end side within the furnace body 11 for holding a wafer W and a heat insulator 20, for holding at least one end portion of the boat 30 and thermally insulating the inside of the furnace body 11 during heat treatment. The heat storage body 20 includes a sheet of thick heat-shielding plate 23 arranged in the side of boat 30 for the boundary position P, a plurality of thin heat-shielding plate 22 and thick heat-shielding plate 23 provided in the side of the furnace port 12 for the boundary position P and a support body 21 for horizontally supporting the thin heat-shielding plate 22. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vertical heat treatment apparatus that applies heat treatment to a processing target used in manufacturing a semiconductor device or the like.
[0002]
[Prior art]
In the manufacture of semiconductor devices, various heat treatment apparatuses are used to perform processes such as oxidation, diffusion, CVD, and annealing on a semiconductor wafer (object to be processed). As one of such heat treatment apparatuses, a vertical heat treatment apparatus is known. The vertical type heat treatment apparatus mounts a boat supporting a plurality of wafers at predetermined intervals in a vertical direction on an upper portion of a vertical type heat treatment furnace via a heat insulating structure which is a heat insulator, and places the wafers in the furnace. The heat treatment is performed in the soaking region. In this vertical heat treatment apparatus, how to prevent heat from escaping from the furnace port and its surroundings is an important issue in order to achieve uniform heat treatment in the furnace.
[0003]
Therefore, in order to improve the heat insulating effect of the furnace port, there has been proposed a vertical heat treatment apparatus constituted by an opaque quartz heat insulating plate for preventing heat passage as a material of the heat insulating structure (Japanese Patent Laid-Open No. 6-208954). Gazette). Specifically, the heat insulating structure includes a plurality of columns and a plurality of opaque quartz heat insulating plates provided on the columns at predetermined intervals in the vertical direction.
[0004]
[Problems to be solved by the invention]
The heat treatment apparatus described above has the following problems. That is, in the heat retaining body of the heat treatment apparatus, the heat transfer amount (heat passing amount) is controlled by arranging the heat insulating plates having the same thickness at equal intervals. However, the amount of heat transfer cannot be reduced below a predetermined value, and there is a limit to the expansion of the soaking area for heat treatment of the wafer, that is, the increase in the number of processed wafers.
[0005]
In view of the above, an object of the present invention is to provide a heat treatment apparatus having a heat retaining body capable of reducing the amount of heat transfer in order to increase a heat equalizing region and increase the number of treatments of an object to be processed.
[0006]
[Means for Solving the Problems]
In order to solve the above problems and achieve the object, the heat treatment apparatus of the present invention is configured as follows.
[0007]
(1) A heat treatment apparatus for performing heat treatment on a plurality of objects to be processed, a heat treatment container having an opening at one end thereof, and an object disposed at the other end of the heat treatment container and holding the object to be processed. A holding part, and a heat retaining body that retains at least one end of the object-to-be-processed holding part and keeps the inside of the heat treatment container at the time of heat treatment; One thick heat insulating plate, a plurality of thin heat insulating plates disposed on the opening side with respect to the boundary position, and stacked and arranged at a predetermined interval; And a support for horizontally supporting the heat insulating plate.
[0008]
(2) The heat treatment apparatus according to (1), wherein the boundary position is λ, the thermal conductivity of the thick heat insulating plate and the thin thermal insulating plate is T, the temperature of the boundary portion is T, and the temperature of a minute distance. the difference [Delta] T, [Delta] Z a minimum interval can be installed above the thin insulating plates, the Stefan Boltzmann factor sigma, the view factor F _a, the black level relationship is taken as F _{E,
λΔT / ΔZ = σF A F E} (T 4 - (T-ΔT) 4)
Is a position at which
[0009]
(3) The heat treatment apparatus according to (1), wherein the number of radiations between the thin heat insulating plates is increased by reducing the thickness of the thin heat insulating plate and narrowing the predetermined interval. Is increased.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a vertical sectional view showing a vertical heat treatment apparatus 10 according to a first embodiment of the present invention. The heat treatment apparatus 10 includes a furnace main body 11 having a hollow portion 11a and formed of a heat insulating material. A furnace port 12 is provided at a lower portion of the furnace body 11.
[0011]
A heater 13 is provided on a wall surface of the hollow portion 11a of the furnace body 11, and a furnace core tube 14 is further provided. Further, a heat insulator 20 is provided from the bottom of the hollow portion 11a of the furnace body 11, and a boat 30 on which the wafer W is mounted is provided above the heat insulator 20.
[0012]
The heat retaining body 20 is provided with a support member 21 formed in a cylindrical shape. A plurality of furnace-port-side thin heat insulating plates 22 are arranged below the boundary position P of the support member 21, and a boat-side thick heat insulating plate 23 is arranged above the boundary position P. The heat insulator 20 is formed of opaque quartz in which bubbles for absorbing heat are dispersed.
[0013]
Here, the difference between the amount of heat transfer by heat conduction and the amount of heat transfer by radiation will be described. That is, as shown in FIG. 2, when the temperature difference is equal, the amount of heat transfer by heat conduction is constant regardless of the temperature. On the other hand, the amount of heat transferred by radiation increases as the temperature increases, even if the temperature difference is equal. Therefore, in a high-temperature region where heat conduction is less likely to be conducted by heat conduction, the amount of heat conduction can be reduced by performing heat conduction by heat conduction using a single thick heat insulating plate. Further, in a low temperature region where heat is less likely to be transmitted by radiation, as many thin heat insulating plates as possible can be arranged and the number of radiations can be increased to reduce the amount of heat transfer. Note that the number of thin heat insulating plates is determined by the workability of the thin heat insulating plates themselves and the workability of the support material 21 as to how close the gaps between the thin heat insulating plates can be arranged.
[0014]
Next, a method of setting a boundary position P between the furnace-port-side thin heat insulating plate 22 and the boat-side thick heat insulating plate 23, which is a position where the amount of heat passing by heat conduction and the amount of heat passing by radiation are balanced, will be described.
[0015]
The thermal conductivity of the material constituting the furnace-port side thin insulation plate 22 and the boat-side thick insulation plate 23 is λ, the temperature is T, the temperature difference is ΔT, the minimum workable interval is ΔZ, and the Stephan Boltzmann coefficient is σ. If the coefficient is F _A , the blackness relationship is F _E, and the amount of heat transfer by heat conduction is on the left side, and the amount of heat transfer by radiation is on the right side, the equation (1) is obtained. That is,
_{λΔT / ΔZ = σF A F E} (T 4 - (T-ΔT) 4) ... (1)
It becomes. By setting the boundary position P in the heat retaining body 20 based on the equation (1), one boat-side thick heat insulating plate 23 is disposed in a higher temperature region (boat 30 side) than when the equation (1) is satisfied. In the low-temperature region (on the furnace port 12 side), the furnace port-side thin heat insulating plate 22 is formed as thin as possible and arranged at narrow intervals.
[0016]
Here, the following conditions are set as an example. That is, the heat retaining body 20 has a total height of 500 mm and a diameter of 300 mm. The temperature of the heat insulator 20 is 1200 ° C. in the upper part, 500 ° C. in the lower part, the minimum thickness of the workable thin-walled heat insulating plate 22 and the minimum distance ΔZ between the workable thin-walled heat insulating plate 22 are 10 mm. . Further, the shape factor calculated from the shape and interval of the furnace-port side thin heat insulating plate 22 is F _A , and the heat conductivity λ of the furnace-port side thin heat insulating plate 22 and the boat-side thick heat insulating plate 23 is 1.6 × 10 ^{−. 3} W / mm ℃, 0.5 blackness relation _{F E,} the Stefan Boltzmann coefficient σ and ^{5.6687 × 10 -14 W / mm 2} K 4.
[0017]
When the boundary position P is calculated based on the equation (1), there is a case where the thickness of the boat-side thick heat insulating plate 23 is 280 mm, and 11 furnace-port-side thin heat insulating plates 22 having a thickness of 10 mm are arranged at intervals of 10 mm. In addition, the amount of heat transferred through the heat retaining body 20 is minimized. FIG. 3 is a diagram illustrating a relationship between the thickness of the boat-side thick heat insulating plate 23 and the heat flux passing through the heat retaining body 20 based on the expression (1) in the present embodiment.
[0018]
As described above, by minimizing the amount of heat transfer in the heat retaining body 20, it is possible to expand the heat equalizing region where the wafer W is heat-treated, and to increase the number of processed wafers.
[0019]
It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the spirit of the present invention.
[0020]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, in order to enlarge a heat equalization area and to increase the number of processes of a to-be-processed object, it becomes possible to reduce the amount of heat transfer.
[Brief description of the drawings]
FIG.
FIG. 1 is a diagram showing a configuration of a vertical heat treatment apparatus according to one embodiment of the present invention.
FIG. 2
The figure which shows the relationship between the thickness of the boat side thick heat insulation board in the same heat processing apparatus, and the heat flow velocity which passes through a heat insulator.
FIG. 3
The figure which shows the relationship between the temperature of a boundary position, the amount of heat transfer by radiation, and the amount of heat transfer by heat conduction.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Heat treatment apparatus 11 ... Furnace main body 12 ... Furnace opening 20 ... Heat retaining body 21 ... Supporting material 22 ... Furnace opening side thin insulation board 23 ... Boat side thick insulation board 30 ... Boat

Claims (3)

In a heat treatment apparatus for performing heat treatment on a plurality of objects to be processed,
A heat treatment container having an opening at one end thereof,
An object-to-be-processed holding part that is arranged at the other end side in the heat treatment container and holds the object to be processed,
A heat retaining body that retains at least one end of the object to be processed and heats the inside of the heat treatment container during heat treatment,
The heat insulator is disposed on the opening side with respect to the boundary position, with one thick heat insulating plate disposed on the processing object holding portion side with respect to a predetermined boundary position, and laminated with a predetermined interval. A heat treatment apparatus comprising: a plurality of thin heat insulating plates formed as described above; and a support that horizontally supports the thick heat insulating plates and the thin heat insulating plates. The boundary position is the thermal conductivity of the thick heat insulating plate and the thin heat insulating plate is λ, the temperature of the boundary is T, the temperature difference of a minute distance is ΔT, the minimum interval of the thin heat insulating plate that can be installed is ΔZ, Stefan Boltzmann factor sigma, the view factor F _a, the black level relationship is taken as F _{E,
λΔT / ΔZ = σF A F E} (T 4 - (T-ΔT) 4)
The heat treatment apparatus according to claim 1, wherein: 2. The heat insulating effect according to claim 1, wherein the thickness of the thin heat insulating plate is reduced and the predetermined interval is narrowed, thereby increasing the number of radiations between the thin heat insulating plates and increasing the heat insulating effect. Heat treatment equipment.

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